Devices to reduce wind resistance and drag on roadway vehicles, such as large trucks, are well known in the prior art. The most common of these devices is a fixed inclined wind deflector at the top of the driver's cab in a tractor trailer vehicle. There are also some prior art teachings relative to folding devices of this character for the front and/or rear of the vehicle which can be detached and stored in a rack beneath the vehicle. It is a general objective of this invention to improve on the known prior art by providing airfoil devices for roadway vehicles of increased operational efficiency and greater simplicity of construction, thereby rendering them more practical and economical.